Brake shoe construction



Y- R. J. BURROWS ET AL 2,097,584

BRAKE SHOE CONSTRUCTION Filed May 12. 1956 Patented Nov. 2, 1937 i UNITED STATES i V 7 Robert J. Burrows and Alfred o. vviiiiamgiiat'. .1: r V I tle Creek, Mich., assignors to .Clark Equipment Michigan :illhisinvention relates to brake/shoe constructions, and more particularly is directed? to the mounting ofa brake .shoe on a. brake supporting. head.for..mo'vement toward and. away from thef 5' associated surfaceto be braked.

'.It has..been customary heretofore to: mount brake shoes of the segment type, which are adapt ed to cooperate with the tread portions of the wheels of vehicles such as rail cars and the. like,

If? by means of a. brake shoe key. on a supporting head. Thesupporting head in such instances is carried on a brake beam which moves the head and shoe bodily toward and away from the tread surface of. the wheel. This results in arcuate 1% movement of the brake surface of the shoe and.

ness. between the parts results inrattling andv wear ng h QE'ItiS the primary object of the present inven tioneto mountthe brake shoe on a pivot pin carried--by; the brake head, whereby the shoe .has gi pivotal-movement. into and out of engagement with;.the surface with which it is associated. This .-:tends to equalize the contact of the shoe against the brake surface so that uniform wear of the shoe surface is produced.

Another object of the present invention is to provide resilient means engaging the lateral surface of the shoe to produce frictional pressure engagement thereon which prevents rattling of the shoe with respect to the supporting head, and at the sametime frictionally holds the shoe in approximate operative position.

Still. another feature provided by the present invention is the provision of take-up means,

H whereby upon predetermined wear of the brak- 40 ing surface on the shoe, the pivotal support of the. shoe with respect to the arm or supporting headtcan be. changed to take up this wear and. results inproper braking effort being applied with.

the same movement of the supportinghead.

45 Another object of the present invention is to provide stop means for limiting rotation of the shoe about its pivotal support in order to maintain it in proper operating position.

Other objects and advantages of the present. construction will be more apparent from the fol-.

and operation of a preferred form of the presentl 55'Sinvention.

Company, Buchanan, Mich, a, corporati'onof Application ay 12, mantra. nemesis f A v 4 9Olain s. 0L1885230) Figureil is auside: elevational view of .the brake shoe.and-supportinghead; and a I Figure. 2;- is an BIId/GIEVMlOIIELViQW, partly in. section,;of the assemblyggshown in Figure '1.

.. Referring; now.to Ltheadrawing in; detail, we.

have disoloseda brake. shoe, indicatedgenerally at5,.having the arcuatereinforced. portion. 6 provided. at .its .outerzzedge with. the tapered brake surface 1 which is adapted to engage the corresponding tapered rimportion of a car wheel or thelike. The shoe 5 is provided with reinforcing rib-portions 8 which terminateat the rear end of the shoe in the thickenedbosses 9 and II]. Intermediate :thereinforcing. ribs 8, the shoe .is provided with theboss portion; I2. which. extends coplanar with the defining surfaces of'the bosses 9 and;'l 0 and projectsforwardly thereof.

. A brake s upportinghead l5 isprovidedhaving the cylindrical collar portion I6 engaging about.

the external surface of anoperating rock shaft [1 which ,extendsthrough-the collar l6 and is connected; to any suitable operating brake mechanism. The head I5 is provided with a bifurcated arm portion I8 having the parallel extending arms l9 andZU Which are spaced apart adistance such as to receive .therebetween the boss portions 9 and In of the shoe 5. e

The arm I9 is provided with the laterally offset portion 22 which terminates in spaced bosses 23 and 24 disposed in alignment with the boss portions 9 and IU of the shoe 5. Each of the bosses 23 and 24 is provided with an axially extending bore 25 which'is adapted to receive the coiled spring 26 biasedbetwe'en' the friction-plate 21 and a spring follower 28 which is threaded into an Iii enlarged portion of thebore 25. The follower 28. in each of the bores is provided with a reduced projecting stud29 which centers the outer end of the spring 25, while the friction plates 21 are thereto. These friction plates on their inner face surfaces bear against the lateral surfaces of the boss portions 9 and H] of the shoe 5, holding the shoe against rattling between the arms l9 and 20 and also serving as friction elements to support the shoea'gainst rocking movement with respect to the supporting head I 5 Q y The head 15 adjacent the collar portion" I6 is provided with anormally extending offset 132 threaded to reoeivethe stop pin 33 threaded therein-into a pos ition such that the head ofthefl-pin engages'the lowerportion-of the brake shoe 5 to hold it in a position extending'sub- It will be stantially at right angles" to the head I 5. The pin 33 is provided with a lock nut 34 to hold it in any desired fixed position with respect to the ofiset 32. r

The boss portion 12 of the shoe 5 is disposed between the forwardly extending portions 35 of the arms l9 and 20, and is pivotally supported therebetween by means of the pin 36 which ex tends through suitable openings in the portions 35 of the arms and through a corresponding opening in the boss portion l2 of the shoe.

held in position by'means of the cotter keyfl, I

It will be noted that the shoe S-between the boss portions 9 and I0 thereof hasa second opening 38 extending laterally therethrough'which is" disposed rearwardly of aligned openings" 39" formed in each of the arms l9 and 20 intermediate the bosses 23 and 24. When the surface .I

tent, it will be obvious that in order to'produce braking pressure, the head l5 InuStibB rotated tola greater extent aboutth'e center of the shaft l1. As this conditiont-occura'it becomes nec-iessary to takeru'p for this: wear, and this is ;ac-

commodated by 'removingsthe pin :36 from theposition shown in Figures 1 and 2, moving athe shoe 5forward1y toalignztheopenings 38 and 39 and then insertingxthe .pin' 36 into these aligned openings. Due to the-fact that the openings 38 and 39 are offset with respect to each other in -the initial: position of the shoe, it' will be apparent that as the surface I wearsdown and the shoe is moved forwardly to bring these openings into Ialignment, the shoe "will be positioned in substantially the same: relative engagement with the head I5, the centers of the openings 38 and 39 being spaced apart a distance slightly less than the equivalent wear of the shoe which 'can be accommodated before such take-up is necesary I 5 I. 1 ca-l. fl pparent that by the-present con;- struction we provide a brakeshoe pivotally supported on a brake'head 'with'f'ri'ction means'resiliently pressed against lateral surfaces on the shoe to prevent the shoe from rattling with re spect to the brake head and to hold the shoe against free swinging movement about its'pivotal support. Also, by reason of the single pivotal mounting of theshoe, itis' obviouslthat the shoe 5 can shift or'rock about its pivot so that the.

brake surface I has full equalized braking contact with respect tothe associated'wheel, the shoe being free to accommodate'itselflto this position during the. arcuate movement of the head l5." Also, the adjustable stop pin prevents the; shoe" 7 from falling out of operative-position with re-' spect toithe head or 'moving into cockedengagerment with the wheel surface.

It is tojbe understood thatthe' spring rdndwer's 28, may bemade adjustable in order'to vary the pressure on thefriction plates .21 if so'desired, or

they can beremoved anan'ew springs inserted whenever desired Also, it is to be understood that the spacing between the'center of the bosses 3,5 of the arms liland 20 andthe eenters of the openings 38;and 39 can'be varied to meet dif v ferent conditions encountered in practice We do not intend to be limited to the specific construction which wehave shown and described,

inasmuch as various equivalent means maybe employed for accomplishing the same purpose. The invention is therefore to .be limited. only as definedby the scope and. spirit of the appendedI- claims. iii; 5 1; lip--1 ing the lateral surface of said shoe between said The pin is arms for preventing vibration of said shoe with respect to-said head, and means threading into said bosses f or retaining said resilient means in pressure engagement with said shoe surface.

2; A brake shoe construction comprising a supporting head, having a bifurcated arm portion, a brake shoe' having a boss portion received within said bifurcatedarm portion, a pin pivotally of the shoe 5 wears down to any considerableexsupporting said shoe on said head, and means carried by one arm portion of said head on opp0- having a bifurcated arm portion receiving said' shoe and having a'pair of pin receiving openings spacedapart a distance less than the openings in said shoe, and pin means carried by said arm and adapted to extend through either of-said pair of openings to support said shoe for pivotal movement on said arm, said arm having means normally urged into frictional engagement with; the'lateral surface of's-aid shoe to hold said shoe in position with respect to said arm while accommodating slight pivotal-movement thereof;

- 4. In combination, a brake shoe having a pair of .spaced ipin receiving openings, abrake armadapted to support said shoe and having a pair of pin receiving openings spaced apart a distance diiferent, than, the spacing of said shoe'openings,

a pinadapted toextend through either pair of openings: for "supporting said' shoe pivotally on said head, and friction means normally holding;

the shoe in position with respect to said head but permitting pivotal imovement I of said shoe with respect to said head during braking engagement of saidshoe. v H v '5. A brake shoe construction comprising'a brake supporting head having a pair of spaced normally extending bosses, a brake shoe carried bysaid head, means pivotally mounting said shoe on said head intermediate said bosses, friction plates carried by said bossesand engaging the lateral surface, of said shoe on opposite sides of said pin, and spring means normally urging said'fric tion plates into pressure'engagement with said surfaces.- 1 6. In combination, a rockshaft, a brake arm supported for conjoint movement with said shaft and. having a pair of spaced arm portions, a brake shoeihavingya boss received within said arm portions,'a pivot pin carried by said arm portions and engaging said shoe for pivotally sup.

porting said shoe on said arm, means'for shifting the point of pivotal support of said shoe with re spect to said arm, and friction means on one side of one of said arm portions and engaging said shoe for normallymaintaining said shoe in positionwith respect to said arm.

'1. Asupporting head for a brake shoe compris II 7 ing a pair of parallelly extending arm portions adapted to receive the web of the brake shoe therebetween, one of said arm portions having spaced normally extending threaded bosses, friction means in the inner end of said bosses engaging the lateral web surface of said shoe, spring means in said bosses biased at one end against said friction means, and closure means threaded into the outer end of said bosses and engaging the opposite ends of said spring means.

8. The head specified in claim 7 characterized by a series of pivot pin openings in said arm portions between said bosses and extending in a direction normal to a line passing through said bosses.

9. A supporting head for a brake shoe, comprising a hub portion adapted to be mounted on an operating shaft, a pair of radially extending axially spaced arms adapted to receive the web of a brake shoe therebetween, a series of pivot pin openings in said arms for receiving a pin pivotally supporting said shoe therebetween, spaced normally extending bosses on one of said arms adapted to contain resilient friction means engaging one lateral surface of the web of said shoe upon opposite sides of the pivot pin support therefor, and an integral normally extending lug adjacent said hub including means for limiting rotation of said shoe in one direction with respect'to said head.

ROBERT J. BURROWS. ALFRED 0. WILLIAMS. 

